#3 prowrap update for new vfs API

[Vince Darley]

Attached patch is a first attempt to update ProWrap to
use the new vfs APIs so that the wrapped filesystem is
much more robust.

Unfortunately, since tclpro's build system is so
astonishingly unfriendly on my platform (Windows), I
haven't even been able to attempt to compile this, so
I can't work on it any further.

[Vince Darley]

diff -bu with windows eols